defmodule ElixirAi.Data.DbHelpers do
  @get_named_param ~r/\$\((\w+)\)/

  def named_params_to_positional_params(query, params) do
    param_occurrences = Regex.scan(@get_named_param, query)

    {param_to_index, ordered_values} =
      param_occurrences
      |> Enum.reduce({%{}, []}, fn [_full_match, param_name], {index_map, values} ->
        if Map.has_key?(index_map, param_name) do
          {index_map, values}
        else
          next_index = map_size(index_map) + 1
          param_value = Map.fetch!(params, param_name)
          {Map.put(index_map, param_name, next_index), values ++ [param_value]}
        end
      end)

    positional_sql =
      Regex.replace(@get_named_param, query, fn _full_match, param_name ->
        "$#{param_to_index[param_name]}"
      end)

    {positional_sql, ordered_values}
  end
end